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2 in. NPT Pressure Vacuum Vents
2 in. NPT Pressure Vacuum Vents
2 in. NPT Pressure Vacuum Vents
One Year Manufacturer Warranty

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Morrison Brothers 749 / 749T 2 in. NPT Pressure Vacuum Vents

for Underground and Low Volume Tanks

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Select Model & Quantity:

Model # Description Price Qty
749---0100 AV 8oz/sq.in. $89.00
749T--0200 AV Slip On, Teflon, 8oz/sq.in. $350.99
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Morrison Brothers 749 / 749T 2 in. NPT Pressure Vacuum Vents
Pressure vacuum vents are installed on the top of underground and low volume aboveground storage tank vent pipes. Vent allows tank to "breathe" during filling and discharging operations. Pressure and vacuum poppet seal vapors in tank when pressure is equalized. Settings are approximate. The 749T provides the same functions as the 749 and is designed for use on underground and low volume aboveground tanks storing Diesel Exhaust Fluid (DEF) and other products requiring Teflon and stainless construction.

  • Screen protects the tank from debris and insects
  • Integrated internal drain port channels water away from the tank
  • Vent vapors up and outward per NFPA 30
  • Conserves fuel
  • Certified CFH ratings
    • Body and hood are anodized aluminum (749T ­ is Teflon® coated aluminum)
    • Pressure poppet is anodized aluminum (749T ­ is HDPE)
    • Vacuum poppet is brass vacuum (749T ­ is stainless steel)
    • Body seal is Buna-N (749T ­ is Viton®)
    • Screen is 40 mesh brass (749T ­ is 40 mesh stainless steel)
    • Springs are stainless steel
    • Set screws are Zinc-plated steel (749T ­ is Nylon)

    WARNING: DO NOT FILL OR UNLOAD FUEL FROM A STORAGE TANK UNLESS IT IS CERTAIN THAT THE TANK VENTS WILL OPERATE PROPERLY. Morrison tank vents are designed only for use on shop fabricated atmospheric tanks which have been built and tested in accordance with UL 142, NFPA 30 & 30A, and API 650 and in accordance with all applicable local, state, and federal laws. In normal operation, dust and debris can accumulate in vent openings and block air passages. Certain atmospheric conditions such as a sudden drop in temperature, below freezing temperatures, and freezing rain can cause moisture to enter the vent and freeze which can restrict internal movement of vent mechanisms and block air passages. All storage tank vent air passages must be completely free of restriction and all vent mechanisms must have free movement in order to insure proper operation. Any restriction of airflow can cause excessive pressure or vacuum to build up in the storage tank, which can result in structural damage to the tank, fuel spillage, property damage, fire, injury, and death. Monthly inspection, and immediate inspection during freezing conditions, by someone familiar with the proper operation of storage tank vents, is required to insure venting devices are functioning properly before filling or unloading a tank.

    WARNING: Fig. 749 P/V vent must only be used in conjunction with motor fueling and/or low capacity flow. Fluid handling in lines larger than that used for retail service stations can cause tank to rupture or implode.